JPH1067876A - Molded plastic foam containing powder of palm shell fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded plastic foam improved in biodegradation rate by compounding a biodegradable plastic with a compressed dry powder of fibers contained in palm mesocarp. SOLUTION: After palm mesocarp is immersed in pure water for 12-16 days to dissolve its sarcocarp, fibers are collected and exposed to the sun for 1 year or longer to remove salts, tannin, etc., contained therein. The fibers are then hotair dried, and the resultant microfibrous component is compressed and ground to give a compressed dry powder having a length of 80-1μm. 95-60wt.% biodegradable plastic or a mixture comprising 85-10wt.% biodegradable plastic and 10-85wt.% nonbiodegradable (petroleum-derived) plastic is compounded with 5-40wt.% above-obtd. compressed dry powder to give a compsn., which is melted by heating to 100-200- deg.C and is molded into a desired shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biodegradable plastic or a petroleum-based non-biodegradable plastic or a mixture thereof, and is obtained by blending a powder obtained by compressing and drying a fiber contained in the mesocarp of a coconut palm. The present invention relates to a molded product of a foamed plastic mixture of coconut shell fiber powder (hereinafter referred to as a foamed product of the present invention).

[0002]

2. Description of the Related Art In general, non-biodegradable foamed plastics are not decomposed in soil or the like, and therefore, the processing after use of foamed polystyrene or the like, which is often used as a buffer material for trays and boxes, has increased in volume due to foaming. Only had been a troublesome problem.

As a means for solving such a problem, a biodegradable plastic foam such as an aliphatic polyester such as polylactic acid and polylactone, a modified starch, and a modified polyvinyl alcohol composite is used in place of the polystyrene foam. The method used has been proposed.

[0004] Recently, biodegradable plastics that are being developed include natural polymers based on polysaccharides such as starch, and microbial polyesters based on the action of microorganisms.
It is roughly classified into a blend system in which additives for promoting decomposition are added to general-purpose plastics, and a chemical synthesis system containing aliphatic polyester, and is used as a raw material for various products according to each material. Has a limited effect.

[0005]

That is, even in the case of the above-mentioned biodegradable foam material, it takes a long time of three months or more to decompose any of the biodegradable foam materials. To cope with this, a foam material that can be biodegraded in a short period of time (within 1 to 2 weeks) is strongly desired.

[0006] By the way, the palm which the present inventor focused on usually means coconut, which is a fruit widely produced in the tropics and has been used in various ways. However, as shown in FIG.
The endocarp 2a having a thickness of m is woven from a fiber (hereinafter, referred to as coconut shell fiber) to a rope and a string, and is not used for other purposes. There was a problem that required land.

As shown in the enlarged view of FIG. 2B, the coconut shell fiber 3 has a sawtooth-shaped projection 3b on the luminal membrane 3a and a hole of the cell membrane penetrating therethrough, and has a length of about 0.7 mm. It has a thick film fiber structure of about 20 μm and is light, stiff and elastic, and has poor heat resistance and durability to air and water (Toyo Keizai Shinposha, edited by Shoichiro Nagai, “Inorganic Organic Industry” Materials Handbook, p. 788, etc.). Furthermore, when it is compressed, it has the property of expanding its volume 5 to 6 times when water is added. It is presumed that this phenomenon is caused by memorizing the shape of the compressed dry fiber when it was in a natural state and restoring the state to a luminal membrane holding state at a cell level.

It is an object of the present invention to obtain a foamed plastic molded article in which decomposability in soil is promoted by utilizing the vegetative properties and shape resilience of the compressed dry powder obtained from the coconut fiber. .

[0009]

Means for Solving the Problems The present inventor has remarkably increased the decomposition rate of biodegradable plastics by blending a predetermined amount of powder (hereinafter referred to as coconut powder) obtained by compressing and drying coconut shell fiber. It was found to be improved and used for the production of a biodegradable foamed plastic molded article (foam molded article I of the present invention).

Further, noting that coconut shell fibers are vegetable and that plant pathogens have a tendency to prefer petroleum-based polyesters, petroleum-based non-biodegradable plastics or biodegradable plastics are used. The mixture of the non-biodegradable plastics and the coconut shell fiber compressed and dried powder are blended, respectively, and subjected to a foaming treatment to obtain molded products (foam molded products II and III of the present invention).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As a biodegradable plastic used in the production of the foam molded article of the present invention, polylactic acid aliphatic polyester resin, modified starch, modified polyvinyl alcohol composite and the like can be used as a foaming material. , A biodegradable aliphatic polyester from the viewpoint of moldability and biodegradability, and non-biodegradable petroleum polyester, polyethylene,
Polystyrene is particularly preferably used.

Hereinafter, description will be made with reference to the drawings. FIG.
(A) is a block diagram showing a raw material composition of the foam molded article of the present invention, and (B) is a block diagram showing a production method thereof.
The production method comprises three steps: treatment of coconut shell mesocarp 2a, treatment of coconut powder 5, pelletization of coconut powder and plastic mixture 4, 4 ', and foaming treatment.

That is, the coconut powder is produced by immersing the mesocarp 2a in fresh water for 12 to 16 months to dissolve the flesh, collecting only the fiber, exposing it to the sun for one year or more, and containing the salt and tannin contained therein. , And further subjected to forced drying with hot air for about 8 hours to reduce the water content to 10%, and then fine components as residue remaining during processing of a rope or the like using the same, or fine components obtained by forced cutting. After fibrous material is collected, collected and once compressed, the length is 80-
Coconut powder 5 of 1 μm is obtained. Next, this coconut powder 5 is dried with hot air at 70 ° C. for 5 to 8 hours to further reduce the water content to 2 to 3%, and is blended so as to have a total weight ratio of 5 to 40% with respect to the biodegradable plastic. Then, as shown by a practice arrow, the mixture is heated and melted at 100 to 200 ° C., and then cooled to form pellets 4.

Although not shown, 1 to 10% by weight of an auxiliary agent is selected and added to the raw material of the pellets 4 if necessary for the intended use. That is, in order to obtain a molded product of the present invention, which is color-coded for each product, a surfactant is used in order to improve the mixing and release of the mixed raw materials, and a desired colorant is used. Finally, a foaming material is blended by adding a dispersant or the like, and an appropriate molding process is performed to obtain a foam molded article.

The foamed molded article of the present invention produced by the above-described method, when buried in the soil, has a remarkably improved decomposability as compared with a conventional biodegradable plastic foamed molded article. .

[0016] This is because once the foamed plastic molded article of the present invention is cracked by microorganisms, the coconut powder, which has been infiltrated and absorbed by water, absorbs the water and expands greatly, generating internal collapse pressure. ,
It is thought that this internal stress destroys the outer wall of the molded article, and the microorganisms that have entered through the gaps accelerate the decomposition, thereby creating a situation in which the activity of other microorganisms on the plastic component is also increased. In addition, since coconut powder is a natural organic material, in addition to microorganisms that prefer it, in the case of the foamed molded articles II and III of the present invention, microorganisms that prefer petroleum-based plastic components particularly gather, and thus coconut powder is firstly obtained. It is considered that the decomposition of the components followed by the decomposition of the petroleum-based plastic components to break down the overall shape is the cause of the accelerated decomposition. (1996 5
In the Chemical Daily, the Ministry of International Trade and Industry of Japan and the Institute of Biotechnology of Industrial Technology announced on 17th that plant pathogenic bacteria prefer petroleum polyester. )

It is also possible to laminate or coat a biodegradable film on the surface of the foamed plastic molded article of the present invention such as a food tray, a cup, etc., and further, it greatly inhibits the decomposability of the foamed molded article of the present invention. A non-biodegradable film such as a polyester-based or polyethylene-based film may be laminated or coated on the surface within a range not to be affected.

[0018]

As described above, according to the present invention, the biodegradation rate can be increased by compounding coconut powder with biodegradable plastic or non-biodegradable petroleum polyester, polyethylene, polystyrene, and a mixture thereof. An improved foam molded article is provided. They are,
As it can be applied to all foam molded products such as cushioning materials, food trays, cups, etc., it is attracting attention as one of the major means of reducing garbage while environmental concerns are rising, and composting in waste disposal problems It is very effective in disseminating.

[Brief description of the drawings]

FIG. 1 is a block diagram showing raw materials for a biodegradable plastic foam molded article and a non-biodegradable plastic foam molded article of the present invention and a configuration of a method for producing the same.

2 (A) is a side sectional view of a coconut used in the present invention, and FIG. 2 (B) is an enlarged sectional view of a coconut shell fiber.

[Explanation of symbols]

1: biodegradable plastic 2: coconut palm 2a: mesocarp 3: coconut shell fiber 3a: lumen 3b: sawtooth projection 4: mixture of coconut shell fiber powder and biodegradable plastic (pellet) 4 ': coconut shell Mixture of fiber powder and biodegradable and petroleum non-biodegradable plastic (pellet) 5: Coconut powder 6: Palm shell fiber powder and petroleum non-biodegradable plastic mixture (pellet) I: The present invention using pellet 4 Foam molded product II: Foam molded product of the present invention using pellets 4 'III: Foam molded product of the present invention using pellets 6

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[Procedure amendment]

[Submission date] November 28, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Coconut shell fiber powder mix onset foam [Title of Invention] Plasti <br/> click moldings

Claims (3)

[Claims] 1. A mixed foaming of coconut shell fiber powder, characterized in that 95 to 60% by weight of biodegradable plastic is blended with 5 to 40% by weight of a compressed and dried powder of fibers contained in mesocarp of palm. Plastic molded products. 2. A palm comprising 95 to 60% by weight of a petroleum-based non-biodegradable plastic and 5 to 40% by weight of a compressed dry powder of fibers contained in the mesocarp of the palm. Molded foam plastic product mixed with shell fiber powder. 3. A biodegradable plastic of 85 to 10% by weight and a non-biodegradable (petroleum) plastic of 10 to 8%.
A foam molded plastic product mixed with coconut shell powder, characterized in that 5 to 40% by weight of compressed and dried coconut fiber is mixed with 5% by weight.